One common issue that comes up often during calibration, particularly for new users, is that the amount of chain extended isn’t long enough to connect to the sled. 99% of the time it’s because they are using a top beam that is longer than the stock 10-foot beam design.

To fix this, go to Advanced Settings -> Extend Chain Distance and increase this amount. The default is 1651 mm and this is good for a 10-foot top beam, however, it’s not enough chain for a 12-foot beam. For a 12-foot beam, it’s recommended to change this value to 2032 mm. Note: See @dlang’s comments below in next post regarding other values that may be used.

You may ask why 1651 mm for a 10-foot beam and 2032 mm for a 12-foot beam as they seem to be rather specific numbers… and it’s true, they are specifically chosen because they are multiples of one complete rotation of the sprocket, 63.5 mm. Why this is important is explained here:

Every now and then you may find that you need to readjust the chains back to a known position. This could occur if you power/connection issue and the controller lost it’s position, had a chain skip, took apart something for some reason, etc… Fortunately, there’s a way to reset the chains without a lot of work.
During calibration, after you set the sprockets vertical, you extend the chains out to reconnect to the sled. If your “Extend Chain Distance” is a multiple of a full revolution of the s…

I found 2032 mm put out enough chain for my 12-foot setup so that there was enough slack to reattach the chain the sled in a comfortable position.

I’ve tried to simplify things in my explanation using 63.5 mm vs 6.35 mm. I think it’s easier to explain it this way… people will see the same tooth and same link at the top if they did everything correctly.